docs: def from_cid(cls, cid, **kwargs):
          """Retrieve the Compound record for the specified CID.
  
          Usage::
  
              c = Compound.from_cid(6819)
  
          :param int cid: The PubChem Compound Identifier (CID).
          """
          record = json.loads(request(cid, **kwargs).read().decode())['PC_Compounds'][0]
          return cls(record)